Nuclear reactors for experimentation, power production and other purposes have been in operation within the U.S. and other countries for many years. Such nuclear reactors usually include a water pit or nuclear pool associated with them in some way.
Through years to use, a water pit or nuclear pit accumulates a layer of dirt and debris on the bottom and sides thereof. This dirt and debris can be attributed to chips from cutting operations, the dropping of small items into the pool, general dirt from the atmosphere, and other items which somehow get into the nuclear pool. This debris affects operations in the pool in a number of ways. The debris increases the activity of the pool water by adding additional nuclear material thereto. Also, the debris reduces the visibility which affects the work being performed in the nuclear pool. Further, if a small item is dropped in the pool, it is hard to find and retrieve as a result of debris in the pool.
Previous methods of nuclear pool cleaning include the use of brushes and dust pans attached to probe poles. This method is not only slow and inefficient, but it also reduces the visibility in the nuclear pool during cleaning by stirring up the silt which had settled out of the water. Other methods have suction equipment mounted out of the water, and vacuum equipment used in the water. The mounting of suction equipment outside of the water, however, increases exposure of personnel to nuclear material and creates problems with disposal of nuclear debris.
One such vacuum for a nuclear pool having suction equipment mounted out of the water is disclosed in U.S. Pat. No. 4,374,024 issued Feb. 15, 1983. This device includes injection and suction tubes and a removable, disposable filter for capturing the irradiated materials. Pressurized water is injected into the suction tube through a jet pump nozzle to establish a suction flow through the tube. The suction device is manually positionable by an operator standing at a cry location who extends the device underwater by maneuvering a positioning pole. The pole is pivotally connected to the injection or suction tube by a variable position latching mechanism. The source of pressurized water which is injected into the suction tube is mounted outside of the nuclear pool. As a result, contaminated water must be circulated out of the pool through the source of pressurized water and back into the pool thereby causing exposure of the operator and other persons in the vicinity to nuclear contamination. In addition, the filter means, which is outside the pool, must be discarded and replaced by a new filter means when it becomes full of debris. This also results in unnecessary exposure of the operator to active nuclear material.
An example of a vacuum cleaner for collecting radioactively contaminated particles located in the air is disclosed in U.S. Pat. No. 4,061,480 issued Dec. 6, 1977. This apparatus uses suction to draw radioactive particles through a high efficiency filter which contains the filtered particles in a disposable bladder filter unit for subsequent disposal. The bladder filter unit prevents the escape of filtered radioactive particles to the ambient atmosphere during the operation of the apparatus as well as during disposal. This apparatus is not designed for use in underwater environments.
An example of a conventional pool vacuum apparatus is disclosed in U.S. Pat. No. 3,868,739 issued March 4, 1975. This portable pool vacuum apparatus is designed to move along the bottom of the pool and to draw water and debris through a vacuum head into a filtration chamber within the casing. The water is passed through a plurality of spaced apart cartridge filters and into a manifold-type chamber. The water is then drawn into a pumping apparatus and discharged exteriorly thereof back into the swimming pool. This apparatus is not designed for cleaning nuclear pools and as a result does not include shielding to protect the user from nuclear contamination. Moreover, to change the filters the user must remove the vacuum apparatus from the water and open the casing to the apparatus and physically remove the filters therefrom. Cleaning of the vacuum in this manner would result in dangerous exposure of the operator to radioactive material were such a device used in a nuclear pool.
Another example of a submersible swimming pool cleaner is disclosed in U.S. Pat. No. 3,886,616 issued June 3, 1975. This apparatus relates to a hand-propelled swimming pool cleaner comprising a wheeled frame having a motor driven pump mounted thereon. The pump is adapted to pick up dirt particles or the like from the pool floor and pump the same through a filter to remove the particles from the water. An elongated handle is secured to the cleaner to permit a person at poolside to manually maneuver the cleaner to clean the bottom of the pool. This swimming pool cleaner is not adapted to be permanently submerged in a swimming pool. In addition, to clean this apparatus one must remove it from the pool and manually remove the filters therefrom. Again, this will result in operator exposure to any radioactive materials which may have been collected in the filter of the vacuum.
U.S. Pat. No. 4,154,680 issued May 15, 1979 describes a cleaning implement for swimming pools. This apparatus has a chassis with traction drive and a suction pump mounted on the chassis. A suction nozzle is connected to the suction side of the pump for drawing in settled particles. A filter is connected to the pressure side of the pump for catching the particles. A controlled diving cell which is floodable and clearable in a controlled manner is arranged on the chassis for varying the buoyancy to the apparatus sufficiently to raise and lower it in the water. This device is not useful in the cleaning of nuclear pools since in order to clean this device one must open the housing and manually remove the filter. Manual removal of the filter will, in turn, expose the operator to radioactive contamination.
U.S. Pat. No. 4,240,173 issued Dec. 23, 1980 describes a pool vacuum including an elongated pipe section having a flattened debris pick-up end and a discharge end for discharging debris into a bag which is removably attached to the pipe section. Intermediate the ends of the elongated pipe section is a larger pipe section which is spaced from and sealed to the elongated pipe section to form a fluid discharge chamber surrounding the elongated pipe section. Apertures are formed between the chamber and the discharge end of the elongated pipe section to direct fluid applied under pressure to the chamber rearwardly through the elongated pipe section. This creates a partial vacuum for causing debris located near the pick up end of the elongated pipe section to be sucked up and directed into the bag whenever fluid under pressure is applied to the chamber. This vacuum suffers from several disadvantages which limit its usefulness for cleaning of nuclear pools. First, to clean the bag it must be physically removed from the vacuum apparatus outside of the water thereby resulting in exposure of the operator to radioactive material. Second the source of pressurized water is mounted outside of the pool and requires circulation of the pool water therethrough. As a result, this suction apparatus would expose the operator to radioactive material since nuclear pool water is contaminated with radioactive material.
Another underwater cleaning apparatus is disclosed in U.S. Pat. No. 4,304,022 issued Dec. 8, 1981. This underwater cleaning apparatus includes a chassis having a caterpillar track and a tapered flow duct below the chassis. The flow duct forms lateral openings between a cleaning brush and the tracks and is connected through an opening to a suction duct of a suction pump which conveys the sucked up liquids with the contaminents contained therein into a filter. Due to the increased flow velocity, the static pressure in the flow duct is reduced, so that the chassis is pressed onto the bottom surface of the pool and can overcome severe gradients without sliding. This vacuum is not adapted for cleaning of nuclear pools since the filter means must be manually removed outside of the water to be cleaned causing exposure of the operator to radioactive material.
Yet another pool vacuum system is disclosed in U.S. Pat. No. 3,755,873 issued Sept. 4, 1973. This pool vacuum system includes housing in the form or a canister enclosing a filtration element therein which is directly attachable to a vacuum head by a flexible tube. A pump is disposed in the canister along with a power source for moving the water from the vacuum head through the filter unit. This device may be remotely operated from outside of the swimming pool, however, it must be removed from the pool in order to clean or replace the filter means. Therefore, this system is not adaptable to nuclear pools since it will result in unnecessary exposure of the operator to radioactive material during cleaning and replacement of the filter means.